Core B: Project Summary: The objective of Core B (Mouse Aging Analysis Core ) is to provide a centralized core facility for the PPG at the Yale School of Medicine that will generate and analyze transgenic mouse models to determine the roles of FGF21 on lifespan extension and age-related functional decline across multiple systems. The Core B will allow the PPG to gain mechanistic insights into the pro-longevity effects of FGF21 across multiple organ systems (adipose tissue, liver, bone, CNS and the immune system) using measures of functional decline in aging, longevity and burden of disease as primary endpoints. The Aim 1 of Core B is be work closely with the leader of the Administrative Core and leaders of the research projects, to assist in the experimental design and execution of the animal research phase of the individual projects, and to assure efficiency and standardization of procedures. The Aim2 is To perform an omnibus study with male and female mice examining the effect of inducible overexpression of FGF21 on lifespan and the contribution of adiponectin to FGF21's pro-longevity effect. Aim 3: To determine the cause of death by detailed pathologic examination of inducible FGF21Tg mice and inducible FGF21Tg mice lacking adiponectin. These studies will involve gross necropsies and histological analyses to quantify pathology and disease burden in our mouse models. Dr. Caroline Zeiss (ACVP and ACLAM boarded) will direct these studies as part of the PPG team. The aim4 will perform an omnibus study with male and female mice examining the role of the FGF21-adiponectin endocrine axis on healthspan and age-related functional decline across organ systems.